Magnetic separator.



Patented Jan. I4, |902.

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SPECIFICATION forming part of Letters Patent No. 691,007, dated January14, 1902.

Application tiled November Z6, 1898. Serial No. 697.534. (No model.)

To @ZZ w/wm/ t may concern:

Be it known that I, FRIEDRICH ARTHUR MAXIMILIAN SCHIECHEL, mining engneer,re siding at Frankfort-on-the-Main, Germany, have invented new anduseful Improvements in liagnetic Separatore, of which the following is aspecification.

Myinvention relates toimprovements in the separation of magneticmaterials from nonmagnetic ones, and is especially adapted for theseparation of the so-called weakly magnetic materials from quitenon-magnetic ones or such of lower magnetic susceptibility. Theimprovements are more particularly adapted to be applied to theapparatus shown in the United States Patents Nos. 555,792, 555,793, and555,794, of March 3, 1896, granted to John Price Wetherill, and in myUnited States application, Serial No. 679,030, of April 26, 1898.

I-Ieretofore the strongest magnetic concentration of the lines of forcehas been produced by arranging a south pole close to and opposite eachsharpened north pole. This has been effected either by means of the twopoles of one and the same eleetromagnet or by means of alternating polesof a group of single electromagnets, which of course had to be arrangedin such a manner that the path of the magnetic lines of force takes itscourse as in Sog a so-called closed or annular magnetthat is to say,with the exception of the interruptions where north and south poles faceeach other (i. e., the fields of operation of the magnetic separator)there must be at all points of the path of tbe lines of force sufficientiron masses to allow the lines offorce which are produced in themagnet-coils to return back into themselves without any considerableloss by dispersion into the surrounding medium. The fields which arethus formed at the places of interruption had their greatest density atthe polar edges and there was therefore nothing to prevent the magneticmaterials which were supplied to one pole edge from jumping over to theother pole edge and becoming attached thereto, so that it was necessaryto provide stripping-bands running around both pole edges for thepurpose of removing the adhering particles in order to keep the edgesalways clean for the continuance of the operation. An essentialimprovement in this respect is embodied in the new magnetic separator ofthis invention, in which there are arranged opposite tothe magnetic edgeover which the material to be separated is supplied two separatewedge-shaped magnets having polarities opposed thereto. Thus when thematerial is supplied, for instance, to one north pole two south polesare arranged opposite to the said north pole. The two south poles arepreferably mounted so that one south pole is higher than the north pole,while the other south pole is situated almost vertically below the northpole, so that the said north pole will serve in a well-known manner atthe same time as a partition, on one side of which the magnetic materialfalls,while the non-magnetic material falls on the other side. Theresult of such an arrangement of poles is that the sum of the lines offorce which issue from the north pole divides or spreads itself into thetwo south poles, so that the magnetic field thus produced is mostconcentrated at the supply-pole and is considerably weaker at the twoother poles, the result being that no material can adhere to the latterand the stripping-belts can be dispensed with entirely.

A further great advantage consists also in the influence which can beexerted upon the form and position of the magnetic field. The amount ofthe force of magnetic attraction depends not only on the number of thelines of force, (intensity of the field), but also on the position anddirection of the lines of force relatively to one another. Aparamagnetic body is moved from a place ot' lower intensity to a placeof higher intensity, and the motive force is greater under conditionsotherwise equal the greater the difference of intensities of the twoplaces is. Consequently there would be the greatest force of attraclionin the magnetic field in which, other circumstances being equahthe linesof force have the greatest difference in direction one -to the other. Inthe separating-machine of this invention this object is effectuallyattained by the lines of force issuing from the point ot' one magnetbeing torn apart, so to speak, by the points of the two other magnets,whereby the magnetic iield receives an advantageous bunch-like shape.

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Experiments made with athree-magnet machine Aand with atwo-magnetmachine which operated under otherwise completely-identical conditionshave proved that the threemagnet machine consumed only forty per cent.of the electrical energy which was required by the two-magnet machine toeffect the separation of one and the same mixture of ore.

A third advantage may be obtained with mixtures of minerals which are tobe separated and which are of that kind that are free from strongmagnetic constitutentsw iron, magneticiron, magnetic pyrites, roastedspathose ironstone, &c.-namely, that also the last stripping-band overthe supplp-pole may be dispensed with.

It is important for the separation of weak magnetic materials that theyshould be supplied in direct proximity to the pole edges and with theleast possible velocity to the gap between the pole edges. This hasheretofore been effected chiefly by means of bands which passed aroundthe pole edges, but which were liable to Very rapid wear and whichnecessarily kept the material distant from the magnetic edge to theextent of the thickness of the band. The conveyer bands can now bedispensed with, as the mixture is supplied directly onto the surface ofthe magnet toward its edge and is left free at the edge without beingconveyed by artificial means around the edge. For this purpose eitherthe surface must have a suitable inclination, in order to allow thematerial to move by its own weight and overcome its own friction on thesaid surface, or artificial means of movement must be employed whichremain above and do not move around the edge of the magnet. The materialis preferably supplied close behind the magnet edge onto the surface ofthe magnet in regulated quantity and in such manner as to meet the saidsurface with the least possible velocityand then move along on the saidsurface. For this purpose a feed-hopper is preferably employed thedelivery-aperture of which is directly behind the magnet edge, andwhence the comminuted material falls out in such manner that it strikesat a small distance above the surface of the magnet first upon atransverse lip and then passes from the latter on the magnet. Thisadmits of the magnet edge being made as sharp as possble,so as both toconcentrate the lines of force as much as possible and prevent themagnetic particles from permanently adhering, since the adhesion isgreater to a broad than to a very narrow edge. The operation ofseparation then takes place, as follows: The non-magnetic particles flowat once over the pole edge and fall off, while the magnetic particleshave at first a tendency to adhere to the magnet edge, but are pushedonward by the material following and carried of comparatively greatsusceptibility-for example, garnet, raw spathose ironstone, dac.-

are to be extracted the cost of manufacture 7o of the apparatus may bereduced, as in this case only the magnet onto whose poles the materialis supplied need be provided with an electric coil, the two other coresthen forming merely the iron masses necessary for the return of thelines of force produced in the magnet. These iron masses must be presentin order that the lines of force shall not become dispersed into the airfrom the whole surface 0f the exciting-magnet, but shall be 8oconcentrated at and pass over thereto from the point of the magnet. Bythus determining the direction of passing over they fulfil the functionof imparting the bunch -like shape to the magnetic field before referredto.

It is obvious that the shape of the magnetic field may be varied at willand that by shifting the two magnets opposite to the supplypole both thedivergence of the bunch of lines of force and the position of the apexor crown 9o of the bunch on the supply-pole can be altered. It is to benoted that, instead of two, three or more magnets might be arrangedopposite to the supply-pole.

The accompanying drawings illustrate a mode of carrying out theinvention which combines all the improvements.

Figure l is a front elevation of the apparatus.

a larger scale.

The upper stirrup shaped magnet B is mounted in an inclined position inthe wooden framing A. It is provided with the charging hoppers or trunksC O and is energized by [o5 means of the coil D. The mixture chargedinto either hopper C mpinges upon and is arrested by a horizontal lip a,whence it falls between the front edge c of this lip and the gage-bar Eonto the magnet B, down which 1ro it slides toward the edge b, which Icall the supply-pole, the gage E being adjustable by means of screws eto regulate the amount of the materialsupplied. Itisimportant that thispole edge b be as sharp as possible in order to prevent a long beard ofmagnetic particles from adhering thereto. This pole edge is brightlypolished or covered with a brightlypolished steel plate in order thatthe particles slipping over it shall be hindered as little as 12opossible by friction. In many cases this covering may be made ofnon-magnetic material i, as shown in Fig. 3, in order to prevent theundermost particles in the stream of material being permanently retainedby the magnet.

Fig. 2 is a section on the line 2 2' of Fig. l. Fig. 3 is a separateview of the poles on roo In consequence of this 13o edges b b, are thepole edges g g of the magnet G. The coils M N of magnets F and Gr may bedispensed with in the case of materials of magnetic properties, such asthose of garnet and spathose ironstone.

Now what I claim as my invention, and desire to secure by LettersPatent, is the following:

l. In a magnetic separator, the combination of a supply-magnet having atapered polepiece, a plurality of magnets the pole-pieces of which areof like polarity with respect to each other, but of unlike polarity withrespect to the supply-magnet, the pole-pieces of similar polarity facingthe pole-piece of the supply-magnet with an intervening space between,and mechanism for feeding the material to be treated over the edge ofthe supplymagnet and between it and the other two magnets.

2. In a magnetic separator, the combination of a supply-magnet having atapered polepiece, and arranged in a horizontally-inclined position sothat the material to be treated will gravitate over its edge, and aplurality of magnets the pole-pieces of which are of like polarity withrespect to each other, but of unlike polarity with respect to thesupplymagnet, the pole-pieces of similar polarity facing the pole-pieceof the supply-magnet with an intervening space between through which thematerial passes from the supplymagnet.

3. In a magnetic separator, the combination of a supply-magnet having atapered polepiece over the edge of which the material to be treatedpasses, and a plurality of magnets the pole-pieces of which are ofopposite polarity to that of the supply-magnet, one of said last-namedmagnets having its polepiece arranged in substantially the verticalplane of the pole-piece of the supply-magnet, and below the same, andthe pole-piece of another of the last-named magnets being arranged insubstantially the horizontal plane ot'- the supply-magnet withintervening spaces between the respective pole-pieces.

4. In a magnetic separator, the combination of a supply-magnet having atapered polepiece and arranged in a horizontally-inclined position sothat the material to be treated will gravitate over its edge, and aplurality of magnets Whose pole-pieces are of opposite polarity to thatof the supply-magnet, one of said last-named magnets havingitspole-piece arranged below and in substantially the vertical plane ofthat of the supply-magnet, and another of said last-named magnets beingarranged in a horizontally-inclined position with its pole-piece insubstantially the horizontal plane of that of the supply-magnet withintervening spaces between the respective pole-pieces.

5. In a magnetic separator, the combination of three magnets havingtapered pole-pieces pointing toward one another with intervening spacesbetween the respective pieces, and over the edge of one of which piecesthe material to be treated is adapted to pass into and through the spacebetween the other pieces.

6. In a magnetic separator, the combination of three magnets havingtapered pole-pieces pointing toward one another with intervening Spacesbetween the respective pieces, over the edge of one of which pieces 'thematerial to be treated is adapted to pass into and through the spacebetween the other pieces, and an energizing-coil on that magnet onlyfrom which the material passes to the intermediate space.

7. In a magnetic separator, the combination of three magnets havingtapered pole-pieces pointing toward one another in a substantiallyradial arrangement, and a central space intermediate the respectivepole-pieces, and means for passing the material to be treated from theedge of one of the pole-pieces into the intermediate space.

S. In a magnetic separator, the combination of three magnets havingtapered pole-pieces pointing toward one another in a substantiallyradial arrangement, some of said magnets having energizing-coils, andothers consisting of cores only.

9. In a magnetic separator, the combination of a magnet having a taperedpole-piece arranged in a horizontally-inclined position, a feed-hopperlocated above said magnet and having its outiiow near the edge of thepolepiece, and a horizontal lip or flange projecting within the hopperto deflect the material slightly just before its passage out of thehopper.

10. In a magnetic separator, the combination of a magnet having atapered pole-piece and arranged in a horizontally-inclined position, afeed-hopper located above said magnet and having its bottom inclined andits outow near the edge of the pole-piece, a horizontal lip or flange onone side of said outflow to deflect the material slightly just prior toits passage out of the hopper, and an adjustable gage at the oppositeside.

Il. In a magnetic Separator, the combination of a vertically-disposedmagnet having a tapered pole-piece, and arranged in the path of deliveryof the material to be treated, said magnet being adapted to receive theseparated constituents of the material on opposite sides thereof, and anadjustable cap of nonmagnetic material secured to the edge of thepole-piece.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRIEDRICH ARTHUR MAXIMILIAN SCHIECHEL.

Witnesses:

OTTO FELLNER, JEAN GRUND.

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